Coupling Efficiency of Intense Laser Pulses to Capillary Tubes for Laser Wakefield Acceleration

The simulations of the coupling of an incident laser pulse to a capillary tube with a cone-shape entrance are presented. The examples of the perfect Gaussian laser pulses and the experimentally measured radial intensity distributions are studied in a vacuum capillary, as well as the excitation of the wakefield inside a gas-filled tube.